This isn't meant to be a slam against Canada in any way...although it will probably be seen as one by Canadians.When it comes to defense Canada...particularly the Canadian Air Force...plays an important role.That role is largely to monitor the vast airspace over what is the second largest country (in terms of area) on earth.Given that there's very close cooperation between the US and Canadian militaries this data is vital for defending North America...a task for which the US and Canada are jointly responsible (Mexico? Don't make me laugh!).
But it must be acknowledged that Canada's Ministry of Defense isn't headquartered in,or near,Ottawa...it's headquartered in Arlington.Virginia.